1. Field of Invention
The present invention relates to an optical path switching device, which utilizes an electric field to drive and control applying electricity on the different reflective elements without moving an input/output end of optical signal or reflective elements, so as to control a travel path of an optical beam to switch the optical path.
2. Related Art
With the development of optical communication network technology, the conventional method of exchanging or routing optical signals depending on high-speed electronic elements has been gradually replaced by processing the optical signals in the optical field to the maximum extent. In other words, through the entire processing, instead of converting the optical signals to electric signals, the optical signals are directly processed to improve the processing speed, and maintain the transparent to light. It can be known from the above that the optical path switching device used as the core for exchanging in the optical field certainly will play a more important role in the future.
The optical path switching device is an device for switching optical signals input from an input port to a destination output port, which can be used in the core technology of all-optical exchange such as in optical cross connect (OXC) and optical add & drop multiplexer (OADM) systems of optical communication network nodes to perform the function of exchanging or routing.
Currently, various types of optical path switching devices are available in the market. In early years, the devices of mechanical type, which use step motors or other mechanical power to move optical fibers, mirrors, or other elements to change the optical paths, monopolize the market. These devices are featured in low crosstalk and low insertion loss, but cannot be easily integrated with other optical communication elements and have low switching speeds and short lifespan, so these devices cannot meet the requirements of the optical communication network gradually. Currently, the micro-electro-mechanical optical path switching devices become the mainstream products, in which a semiconductor material such as silicon is used to engrave micro-electro-mechanical structures, which among others, mainly are micro movable mirror array architecture using actuators to control positions of the reflective elements, such that the reflective elements enter or depart from the optical signal path of the output/input end to achieve the object of optical path switching.
A micro-electro-mechanical 1×2 optical path switching device is given below to illustrate the operating principles of the micro-electro-mechanical optical path switching device. The architecture of the device is as shown in FIGS. 1 and 2. The micro-electro-mechanical 1×2 optical path switching device 100 is composed of an input light collimator 101, a first output light collimator 102, a second output light collimator 103, an actuator control device 104, and a reflective element 105. The micro-electro-mechanical 1×2 optical path switching device is assumed to have an original state as shown FIG. 1, the input light source is directly incident into the first output light collimator 102 to form a first optical path 102. FIG. 2 is a schematic view illustrating the state after the actuator control device 104 of the micro-electro-mechanical 1×2 optical switching device controls the reflective element 105 to enter the input light source. At this time, the input light source is reflected by the reflective element 105 to the second output light collimator 103 to form a second optical path 201. Thus, the switching of the optical path of the input light source is achieved.
In addition, in order to reduce the times that the input light source is reflected by the reflective element, the reflective element can also adopt a manner of moving upward and downward, or rotating in any direction, which can be classified into 2D and 3D array architecture. In the 2D array architecture, the reflective mirror just moves upward and downward simply. When the reflective mirror moves downward, the light can pass through. Otherwise, the light beam will be reflected to a destination output port. In the 3D array architecture, the reflective mirror can rotate in any direction. However, this method requires very precise control over the rest position of the reflective mirror.
The conventional art mainly uses the mechanical motion as the main technical means to realize the control. However, long-term movement often causes deformation of the structure and damages to the material, and the shock in the movement and transportation will reduce the reliability, which will lead to inaccuracy of the control eventually. Moreover, the optical path switching device is also limited by the moving space required by the mechanical motions, so the volume of the device cannot be further reduced.
In view of the problems of the conventional art, the inventor of the present invention provides an optical path switching device utilizing the electro-optic effect to eliminate the dependence of the conventional optical path switching device on the mechanical motions.